The schematic diagram of the solar collector system is shown in
Fig. 4. The two solar water heater systems have a tank for absorbing
the heat energy, respectively. The capacity of the tank is about 100
Lit. In the nanofluids solar cycle, one heat exchanger was used inside
the tank. So the nanofluids can transmit the heat load of the
solar cycle to the water. While in the water solar cycle system, the
tank has no heat exchanger. Two glass rotameters were used to
measure the mass flow rate of working fluid in the solar system.
Two thermocouples (Type K) were used to measure the fluid temperatures in the inlet and outlet of solar collector. The test
precision of thermocouples is ±0.2 C, and they were calibrated by a
precision thermometer. All thermocouples were connected to the
data acquisition system Agilent 34970A. The interval time of data
acquisition is 20 s. The air temperaturewas measured by a platinum
resistance thermometer with a cover for solar radiation protection.
The total solar radiationwas recorded by a TBQ-2 solar meter which
using a calibrated reference solar meter with a valid calibration
certificate. The platinum resistance thermometer and solar meter
were connected to the solar data logger system.